feat(settings): storage budgets and retention in settings UI, tmdbMaxSize default 5000 (INT-3)

- Automation section gets storage budget, retention and cache TTL cards bound to settings.storage
- Metadata section drops deprecated cache.tmdbTtlHours / cache.emptyResultTtlSec / identity.poolArchiveDays inputs
- cache.tmdbMaxSize default 256 -> 5000; migration 0051 bumps stored values still at the old default

Co-Authored-By: Claude Opus 5.5 <[email protected]>

packages/contracts/src/settings.ts

@@ -29,7 +29,7 @@ const CacheShape = z.object({
    * 保留在 schema 里只为兼容已存的 JSON 与旧设置页。
    */
   tmdbTtlHours: z.number().int().min(1).max(720),
-  /** TMDB 缓存每类条数上限,超出删最旧(对照 MP CONF.tmdb,缺省 256;大内存模式 1024) */
+  /** TMDB 缓存每类条数上限,超出删最旧(MP CONF.tmdb 为 256 / 大内存 1024;本项目存 PG 不占进程内存,缺省 5000) */
   tmdbMaxSize: z.number().int().min(16).max(100_000),
   /** @deprecated CACHE-2 起由 storage.cacheTtl.tmdbMissDays 取代,服务端不再读取 */
   emptyResultTtlSec: z.number().int().min(0).max(86_400),
@@ -566,7 +566,7 @@ export const DEFAULT_SETTINGS: GlobalSettings = {
     checkIntervalSec: 60,
     cleanupTargetPercent: 80,
     tmdbTtlHours: 24,
-    tmdbMaxSize: 256,
+    tmdbMaxSize: 5000,
     emptyResultTtlSec: 1800,
     globalImageCache: false,
     globalImageCacheDays: 7,